Highest temperature in London on June 22?

Platform comparison

Active sub-markets

Market context

London City Airport is likely to post its hottest reading for 22 June during the afternoon peak, with the market resolving on the single highest Celsius value recorded before the settlement cut-off. With the current book heavily anchored to **27°C** and a smaller tail in **28°C**, the practical question for a trader is whether the day’s realised maximum can clear the forecast by enough to migrate into the next bin rather than merely touch it. [1][2]

Historically, London’s late-June highs often sit in the mid-to-upper 20s rather than extreme heat, so a 27°C print is consistent with a warm but not exceptional summer day. That makes the current 0% YES crowd price look like a stale or mis-specified read if it refers to a different strike than the live contract, because the venue forecast and live observations both point to a plausible ceiling near the high-20s rather than a collapse back into the low-20s. [2][3][6][8]

For a programmatic workflow, the main inputs are the live Wunderground station feed, the Met Office and BBC station forecasts, and the timing of the day’s maximum relative to the 12:00Z settlement window. A bot or conditional-order setup would typically watch the intraday temperature trace, compare it with neighbouring bin boundaries, and only treat a move as actionable if the observed high is consistent across successive updates rather than a single noisy spike; the Met Office currently shows a 30°C maximum for London City Airport, while BBC lists 28° for Monday 22nd, so any late acceleration in cloud cover or showers would matter more than routine drift. [2][5][9]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in London on June 22? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Is this market available outside the US?

Polymarket App UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What does it cost to trade on Polymarket App UK?

Zero. Polymarket App UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket App UK triggers a quick verification flow that finishes in minutes.